Poly(vinyl diphenylquinoxaline) as a hydrogen storage material toward rapid hydrogen evolution

A safe hydrogen storage method that does not entail high-temperature reactions, high pressures, and explosion risks is required urgently. Herein, we present a polymeric hydrogen carrier bearing 2,3-diphenylquinoxaline as a hydrogen storage unit. The introduction of phenyl group into a heterocyclic nitrogen compound led to rapid dehydrogenation. The radical polymerization of 6-vinyl-2,3-diphenylquinoxline produced poly(6-vinyl-2,3-diphenylquinoxline) with a high molecular weight of ~ 10⁵. The hydrogenation of poly(6-vinyl-2,3-diphenylquinoxline) by a borane–tetrahydrofuran complex resulted in poly(6-vinyl-2,3-diphenyl-1,2,3,4-tetrahydroquinoxaline). The reversible hydrogenation/dehydrogenation of these newly synthesized polymers was demonstrated with full conversion under mild conditions (~ 1 atm and < 200°C). Graphical abstract: [Figure not available: see fulltext.]